N-azolyl sulfenamides

ABSTRACT

SULFENAMIDES OF THE FORMULA   T-N(-R&#39;&#39;)-S-R   WHEREIN R IS ALKYL, CYCLOALKYL, ARALKYL, SUBSTITUTED ARALKYL, ARYL, OR SUBSTITUTED ARYL, WHERE THE SUBSTITUENTS ARE ALKYL, ALKOXY, NITRO, CHLORO, BROMO, FLUORO, IODO OR HYDROXY, R&#39;&#39; IS HYDROGEN RO R&#34;S-WHERE R&#34; HAS THE SAME MEANING AS R AND MAY BE THE SAME OR DIFFERENT FROM R, T IS AZOLYL OR SUBSTITUTED AZOLYL SELECTED FROM THE GROUP OF THIZAOLYL, BENZOTHIAZOLYL, BENZOXAZOLYL, BENZIMIDAZOYL AND SUBSTITUTED DERIVATIVES THEREOF, WHERE THE SUBSTIUTENTS ARE LOWER ALKYL, CHLORO, BROMO, FLUORO, IODO, NOTRO OR LOWER ALKOXY ARE PREMATURE VULCANIZATION INHIBITORS OF VULCANIZABLE ELASTOMERS.

United States Patent O 3,645,987 N-AZOLYL SULFENAMIDES Joseph Edward Kerwootl, Akron, Ohio, assignor to Monsanto Company, St. Louis, M0. N Drawing. Filed Sept. 25, 1969, Ser. No. 861,152 Int. Cl. C07d 85/00, 91/46; C08f 27/06 U.S. Cl. 260-795 B 8 Claims ABSTRACT OF THE DISCLOSURE Sulfenamides of the formula TNSR wherein R is alkyl, cycloalkyl, aralkyl, substituted aralkyl, aryl, or substituted aryl, Where the substituents are alkyl, alkoxy, nitro, chloro, bromo, fiuoro, iodo or hydroxy, R is hydrogen or RS where R has the same meaning as R and may be the same or different from R, T is azolyl or substituted azolyl selected from the group of thiazolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl and substituted derivatives thereof, Where the substituents are lower alkyl, chloro, bromo, fiuoro, iodo, nitro or lower alkoxy are premature vulcanization inhibitors of vulcanizableelastomers.

BACKGROUND OF "THE INVENTION The invention relates to new compounds useful as inhibitors of premature vulcanization in rubber.

In the manufacture of vulcanized rubber products, crude rubber is combined with various other ingredients such as fillers, accelerators, and antidegradants to alter and improve processing of the rubber and to improve the properties of the final product. The crude rubber is put through several steps in the plant before it is ready for the final step of vulcanization. Generally the rubber is mixed with carbon black and other ingredients except the vulcanizing agent and accelerator. Then the vulcanizing and accelerating agents are added to this masterbatch in a Banbury mixer or a mill. scorching, viz, premature vulcanization, can occur at this stage of the processing, during the storage period before vulcanizing, and during the actual vulcanization. After the vulcanizing and accelerating agents are added, the mixture of crude rubber is ready for calendering or extruding and vulcanization. If premature vulcanization occurs during the storage of the crude mixture or during processing prior to vulcanization, the processing operations cannot be carried out because the scorched rubber is rough and lumpy, consequently useless. Premature vulcanization is a major problem in the rubber industry and must be prevented in order to allow the rubber mix to be preformed and shaped before it is cured or vulcanized.

SUMMARY OF THE INVENTION I have discovered a class of sulfenamides which are extremely valuable inhibitors of premature vulcanization.

They are characterized by an azolyl group on the sulfenamide nitrogen and may be represented by the formula Tl 'I-S-R where R is alkyl, cycloalkyl, aralkyl, aryl, or alkaryL R is hydrogen or R"S where 'R" has the same meamng ice as R but is not necessarily the same radical as R, T is thiazolyl, benzothiazolyl, benzoxazolyl or benzimidazolyl. Aryl is a univalent organic radical the free valence of which belongs to an aromatic carbocyclic nucleus and not to a side chain. Both unsubstituted and substituted aryl and alkaryl radicals are suitable for practice of the present invention. The substituents may be alkyl as indicated above (alkaryl) or alkoxy, nitro, chloro, bromo, fluoro, iodo or hydroxy. It is preferred that the carbocyclic nucleus represented by R contain not more than one electronegative substituent. Alkyl radicals are aliphatic radicals of the series C H The alkyl radical may be primary, secondary or tertiary and the primary alkyl may be branched or unbranched. Alkyl radicals of 1-18 carbon atoms are preferred and a preferred subgroup are alkyl radicals of 3-12 carbon atoms. The preferred cycloalkyl radicals contain 512 carbon atoms in the ring a preferred subgroup thereof containing 5-8 carbon atoms.

The azole radicals may be substituted or unsubstituted suitable substituents being lower alkyl, chloro, bromo, fluoro, iodo, nitro or lower alkoxy.

More specific examples of R are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec. butyl, t-butyl, amyl, sec. amyl, tert. amyl, n-hexyl, 2-ethylhexyl, decyl, dodecyl, phenyl, naphthyl, benzyl, phenethyl, p-chlorophenyl, p-nitrophenyl, xenyl, o-tolyl, m-tolyl, p-tolyl, xylyl, p-nonyl, p-t-butylphenyl, cyclopentyl, cyclohexyl, cyclooctyl or cyclododecyl. Other examples of suitable azole radicals are 4-methylthiazolyl, S-methylthiazolyl, 4-ethylthiazolyl, phenyl, 4-chlorobenzothiazolyl, S-chlorobenzothiazolyl 6-ethoxybenzothiazolyl, 5,6-dimethylbenzothiazolyl, 5,6-dimethylbenzimidazolyl, 6-methoxybenzothiazoly1 and 6-nitrobenzothiazolyl. In general the carbocyclic ring of benzothiazolyl, benzoxazolyl or benzimidazolyl may be substituted by lower alkyl, lower alkoxy, halogen or nitro.

Examples of the new compounds of the invention are:

N- 2-benzothiazolyl) ethylsulfenamide,

N- Z-benzothiazolyl) -t-butylsulfe'namide,

N-( 2-benzothiazolyl )-n-hexylsulfenamide,

N- (Z-benzothiazolyl cyclohexylsulfenamide,

N- 2-benzothiazolyl phenylsulfenamide,

N- (Z-benzothiazolyl -p-chlorophenylsulfenamide,

N- (2-benzothiazolyl -p-nitrophenylsulfenamide,

N-( 2-benzothiazolyl)-N-ethy1thio ethylsulfenamide,

N- 2-benzothiazolyl) -N-cyclohexylthio cyclohexylsulfenamide,

N- (2-benzimidazolyl -N- (methyl) -propylsulfenamide,

N- 2-benzoxazolyl -N- n-butyl )phenylsulfenamide,

N- 2-b enzothiazolyl) -N- cyclohexyl) phenylsulfenamide,

N- Z-benzothiazolyl) -N (methyl) -p-chlorophenylsulfenamide,

N- (2-benzothiazolyl) -N- (tert.-butyl cyclopentylsulfenamide,

N- 2-benzothiazolyl cyclooctylsulfenamide,

N- 2-benzothiazolyl -N-phenylthio phenylsulfenamide,

N- (Z-benzoxazolyl ethylsulfenamide,

N- Z-benzoxazolyl -t-butylsulfenamide,

N- (Z-benzox azolyl) -n-hexylsulfenamide,

N- (2-benzoxazolyl cyclohexylsulfenamide,

N- 2-benzoxazolyl phenylsulfenamide,

N- 2-benzimid azolyl ethylsulfenamide,

N- 2-benzimidazolyl -t-butylsulfenamide,

N- Z-benzimidazolyl) -n-hexylsulfenamide,

N- Z-benzimidazolyl) cyclohexylsulfenamide,

N- 2-b enzimidazolyl phenylsulfenamide,

N- Z-thiazolyl ethylsulfenamide,

N-(Z-thiazolyl -t-butylsulfenamide,

N- (2-thiazolyl) -n-hexylsulfenamide,

N- 2-thiazolyl cyclohexylsulfenamide,

N (2-thiazolyl phenylsulfenamide,

N- [2- (4-chlorobenzothiazolyl) ethylsulfenamide,

N- [2 4-chlorobenzothiazolyl) ]-t-butylsulfenamide,

N- [2- 4-chlorob enzothiazolyl) ]-p-hexylsulfenamide,

N- [2- (4-chlorobenzothiazolyl) ]cyclohexylsulfenamide,

N- 2-(4-chlorobenzothiazolyl ]phenylsulfenamide,

N- [2- S-chlorobenzothi azolyl) ]ethylsulfenamide,

N- 2- S-chlorobenzothiazolyl l-t-butylsulfenamide,

N- [2- (S-chlorobenzothiazolyl) ]-n-hexylsulfenamide,

N- [2- S-chlorobenzothiazolyl) ]cyclohexylsulfenamide,

N- 2- 5-chlorobenzothiazolyl) ]phenylsulfenamide,

N- [2- 6-ethoxybenzothiazolyl) ]-ethylsulfenarnide,

N- [2- 6-ethoxybenzothiazolyl) ]-t-butylsulfenamide,

N- [2- (fi-ethoxybenzothiazolyl) ]-nhexylsulfenamide,

N- [2- (6-ethoxybenzothiazolyl) ]cyclohexylsulfesa mide,

N- [2- (6-ethoxybenzothiazolyl) ]phenylsulfenamide,

N- [2- 5,6-dimethylbenzimidazolyl) ]ethylsulfenamide,

N- 2- 5,6-dirnethylbenzimidazolyl) l-t-butylsulfenamide,

N- [2- (5 ,6-dimethylbenzimidazolyl) ]-n-hexylsulfenamide,

N- [2-( 5 ,6-dimethylbenzimidazolyl) ]cyclohexyl sulfenamide,

N- 2- 5 ,6-dimethylbenzimidazolyl) ]phenylsulfenamide,

N- [2- (5,6-dimethylbenzothiazolyl) lethylsulfenamide,

N- [2- 5,G-dimethylbenzothiazolyl) -t-butylsulfenamide,

N- [2- (5 ,6-dimethylb enzothiazolyl) ]-n-hexylsulfenamide,

N- [2- 5,6-dimethylbenzothiazolyl) cyclohexylsulfenamide, and

N- [2- 5,6dimethylbenzothiazolyl) ]phenylsulfenamide.

Rubber stocks containing delayed-action accelerators can be used in the process of this invention. Cheaper, more scorchy accelerators can also be used with an excellent degree of improvement. The improved vulcanizing process of this invention can be used advantageously to process stocks containing other types of blacks and fillers used in rubber compounding. The invention is also applicable to gum stocks.

The invention is applicable to rubber mixes containing sulfur-vulcanizing agents, peroxide-vulcanizing agents, organic accelerators for vulcanization, and antidegradants. The new compounds directly increase process safety of peroxide cures and are preferably used in the absence of organic accelerator when peroxide is the vulcanizing agent. With sulfur-vulcanizing agents organic accelerator will normally be present. Sulfur-vulcanizing agent means elemental sulfur or sulfur containing vulcanizing agent, for example, an amine disulfide or a polymeric polysulfide. Peroxide-vulcanizing agent means any of the organic peroxides which are curing agents for natural and synthetic rubber. One well known curing agent is dicumyl peroxide. The technical literature describes in detail various procedures to effect peroxide cures. Certain patents also describe the use of peroxide-vulcanizing agents, typical of which are US. Pats. Nos. 2,819,255 and 2,819,256 (1958).

The invention is applicable to vulcanization accelerators of various classes. For example, rubber mixes containing the aromatic thiazole accelerators which include N-cyclohexyl-2-benzothiazolesulfenamide, N,N-dialkyl-2- benzothiazolesulfenamide, 2-mercaptobenzothiazole, N- tert-butyl-Z-benzothiazolesulfenamide, 2 benzothiazolyl diethyldithiocarbamate, 2,2'-dithiobisbenzothiazole and 2-(morpholinothio)benzothiazole may be used. Amine salts of mercaptobenzothiazole accelerators, for example, the tbutylamine salt, morpholine salt or 2,6-dimethyl morpholine salt of mercaptobenzothiazole may be used in the invention. Any of the thiazole accelerators may be used. Stocks containing accelerators, for example, tetrarnethylthiuram disuliide, tetramcthylthiuram monosulfide, aldehyde amine condensation products, thiocar bamylsulfenamides, thioureas, xanthates, and guanidine derivatives, are substantially improved using the process of my invention. Examples of thiocarbamylsulfenarnide accelerators are shown in US. Pats. 2,381,392, Smith assigned to Firestone; 2,388,236, Cooper assigned to Monsanto; 2,424,921, Smith assigned to Firestone; and British Pat. 880,912, Dadson assigned to Imperial Chemical Industries limited. The invention is applicable to accelerator mixtures. The invention is applicable to stocks containing amine antidegradants. Rubber mixes containing antidegradants, for example, N-1,3-dimethylbutyl-N'- phenyl-p-phenylenediamine, N,N-bis 1,4-dimethylpentyl) p-phenylenediamine, and other phenylenediamines, ketone, ether, and hydroxy antidegradants and mixtures thereof, are substantially improved using the process of my invention. Mixtures of antidegradants, for example, a mixture of N-l,3-dimethylbutyl-N-phenyl-p-phenylenediamine and N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, furnish a much improved final product when used with the inhibitors of this invention.

The inhibitors of my invention can be used in natural and synthetic rubbers and mixtures thereof. Synthetic rubbers that can be improved by the process of this invention include cis-4-polybutadiene, butyl rubber, ethylene-propylene terpolymers, polymers of 1,3-butadiene, for example, 1,3-butadiene itself and of isoprene, copolymers of 1,3-butadiene with other monomers, for example, styrene, acrylonitrile, isobutylene, and methyl methacrylate. The invention relates to diene rubbers, and the terms rubber and diene rubber are synonymous for the purpose of this invention.

The amount of inhibitor used depends upon the other components in the rubber formulation, the vulcanizing agent used, the accelerator used, the antidegradant used and other process variables which may be unique to a specific application. An experienced compounder can readily determine the amount needed for any particular situation. The amount usually is within the range of 0.1 to 5 parts by weight per parts by Weight of elastomer, and more often within the range of 0.3 to 2 parts by weight. The preferred usage generally falls within the range of 0.5 and 1.5 parts by weight inhibitor.

The compounds may be prepared by reacting the corresponding sulfenyl chloride with 2-aminothiazole, 2- aminobenzothiazole, Z-aminobenzoxazole, 2-aminobenzimidazole, or a substituted derivative thereof in the presence of a hydrogen chloride acceptor. The general reaction is 'r nHCl where n is I or 2 and R and T have the same meaning as before. If different R substituents are desired where n is 2, one mole of RSCl is reacted initially followed by reacting a different RSCl with RSII%T formed in the initial reaction. Typical examples follow:

EXAMPLE 1 N- Z-benzothiazolyl phenylsulfenamide N-(Z-benzothiazolyl)phenylsulfenamide is prepared in the following manner: 14.4 grams (0.1 mole) of benzene sulfenyl chloride dissolved in 38.6 grams of CCL, is added dropwise over a 20-30 minute period between 2030 C. to a stirred slurry containing 15.0 grams (0.1 mole) of Z-aminobenzothiazole, 10.0 grams (0.128 mole) of pyridine, and 200 ml. of benzene. The slurry is held with stirring for one hour, filtered, and washed with benzene. The soluble portion is recovered by evaporation of the benzene and is a pink solid. The material is recrystallized from ethyl acetate to yield 6.0 grams of a solid which melts at C. with decomposition. Analysis of the product gives 10.72% nitrogen and 24.98% sulfur. Calculated percentages for C H N S are 10.77% nitrogen and 24.8% sulfur.

5 EXAMPLE 2 N- (Z-benzothiazolyl) isobutylsulfenamide N-(2 benzothiazolyl)isobutylsulfenamide is prepared by the addition of 97 ml. of a n-pentane solution containing 0.2 mole of isobutyl sulfenyl chloride dropwise over a 15 minute period to a stirred solution of 15.0- grams (0.1 mole) of 2-aminobenzothiazole and 25.0 grams of triethylamine dissolved in 150 ml. of N,N-dimethyl formarnide (DMF) cooled to C. The temperature is maintained between 0-7 C. by cooling with an external ice bath. The cooling bath is removed and the reaction mixture is stirred for 2 hours. The reaction mixture is filtered to remove triethylamine hydrogen chloride. An oil is separated from the filtrate by addition of 3.0 liters of ice water. The oil is extracted with one pound of ether by decanting the Water away from the ether layer. The ether solution is dried over 100 grams of anhydrous sodium sulfate. The material is recovered by evaporation of the ether solution. The yellowish orange solid so recovered is recrystallized twice from heptane. The product melts at 97-99 C. Analysis of the product gives 11-72% nitrogen and 27.03% sulfur compared to 11.87% nitrogen and 26.9% sulfur calculated for C H N S EXAMPLE 3 N- (2-b enzothiazolyl -n-hexylsulfenamide N (2 -benzothiazolyl)-n-hexylsulfenamide is prepared in the same manner as N-(Z-benzothiazolyl)isobutylsulfenamide in Example 2 except n-hexyl sulfenyl chloride is used in place of isobutyl sulfenyl chloride. The product recrystallized from heptane melts at 7072 C. Analysis of the product shows 10.14% nitrogen and 23.15% sulfur. Calculated percentages for C H N S are 10.53% nitrogen and 23.05% sulfur.

EXAMPLE 4 N- (2-benzothiazolyl) cyclohexylsulfenamide N-(Z-benzothiazolyl)cyclohexylsulfenamide is prepared in the following manner: 140 ml. of a solution containing 37.5 grams (0.25 mole) of cyclohexyl sulfenyl chloride in n-pentane is added slowly over a 30 minute period to a stirred solution of 37.5 grams (0.25 mole) of Z-amino benzothiazole and 30.0 grams (0.3 mole) of triethylamine dissolved in 250 ml. of DMF. The temperature rises from 25 C. to 30 C. The reaction is quenched by the addition of 2.5 liters of ice water to the slurry. The amine salt is dissolved and a thick viscous oil results. After decanting the water from the oil layer, ether is added to the oil layer from which a tan solid is crystallized overnight. The tan solid is slurried in a 50/50 mixture of heptane and ethyl alcohol and is filtered. 38.0 grams of a white solid is obtained. This material is recrystallized from toluene two times to yield 27.0 grams of a solid, which melts at 1S6l58 C. Analysis of the product indicates 10.37% nitrogen and 24.13% sulfur compared to 10.62% nitrogen and sulfur calculated for C13H16N2S2.

EXAMPLE 5 N-(2-benzothiazolyl)-N-(phenylthio) phenylsulfenamide 28.8 grams (0.2 mole) of benzene sulfenyl chloride dissolved in 86.2 grams of CCL; is added over a 30 minute period to a stirred solution of 15.0 grams (0.1 mole) of 2-aminobenzothiazole and 25.0 grams (0.2 mole) of triethylamine in 150 ml. of DMF cooled to 5 C. The temperature is maintained between 5 and l0 C. during which a yellow-orange precipitate forms. The reaction mixture is allowed to warm to room temperature. The reaction is quenched by the addition of ice water and a gummy semisolid forms. After decanting the water, a reddish solid is obtained by filtration. This material is recrystallized twice from heptane to give a solid which melts with decomposition at 112-115 C. A portion of the sample is reduced with NaI and is titrated with sodium thiosulfate to give an assay which confirms a bis-substituted compound. Analysis of the product shows 7.68% nitrogen compared to 7.28% nitrogen calculated for 19 14 2 3- The following tables illustrate the improved processing safety obtained by incorporating the new compounds into rubber. For all the rubber stocks tested and described, infra, as illustrative of the invention, Mooney scorch times at 121 C. are determined by means of a Mooney plastometer. The time in minutes (i required for the Mooney reading to rise five points above the minimum viscosity is recorded. Longer times are indicative of the activity of the inhibitor. Longer times on the Mooney Scorch Test are desirable because this indicates greater processing safety. Percentage increases in scorch delay are calculated by dividing the Mooney scorch time of the stock containing the premature vulcanization inhibitor by the Mooney scorch time of the control stock, multiplying by 100, and subtracting 100. These increases show the percentage improvement in scorch delay over the control stock which contains no inhibitor. Additionally, cure ratings are calculated from the time re quired to cure the natural rubber stocks at 144 C. and synthetic rubber stocks at 153 C. Curing characteristics are determined by means of the Monsanto Oscillating Disc Rheometer described by Decker, Wise, and Guerry in Rubber World, December 1962, page 68. From the Rheometer data the maximum torque is recorded in Rheometer units, t is the time in minutes for a rise of two Rheometer units, above the minimum reading and 1 is the time required to obtain a torque 90% of the maxlmum.

The trademarks of some compounds used in the practice of this invention are Santocure MCR, Santocure NS and Santoflex 13. MOR is the accelerator 2-(morpholinothio)benzothiazole and NS is the accelerator N-tertbutyl-2-benzothiazolesulfenamide. Santoflex 13 is the antidegradant N-(1,3-dimethyl butyl)-N'-phenylp-phenylenediamine.

The compounds of this invention are excellent premature vulcanization inhibitors. In a natural rubber masterbatch, the scorch delay is increased 186% when N-(Z-benzothiazolyl)phenylsulfenamide is used.

MASTERBATCH Parts Smoked sheets Furnace black (ISAF) 45 Zinc oxide 3 Stearic acid 2 Hydrocarbon softener 5 Total parts Stock A B C D E F Masterbatch 155. 0 155. 0 155. 0 155. 0 155. 0 155. 0

g;1ll1f1r i\.a 6ii 3.5 2.5 2.5 2.5 2.5 2.5

ocure .5 0.5 0.5

N-(2benzothiazolyl) 0 5 0 5 O. 5

phenylsulfenamide 1. 0

N-(2-benzothiazolyD-N- i (phenylthi0)phenylsulfenamide 1. 0

N (2-benz0thiazolyl) lsobutylsulfenarnide 1. 0

N-(2-benzothiazolyl)-nhexylsulfenarnide 1 0 N-(Z-benzothiazolyl) u s c zelghexllsulfenamlde 1. 0

an 0 ex 2.0 2.0 2.0 2.

Mooney scorch at 121 0.: 0 2 0 2' 0 t5 25. 7 73.1 67.5 52. a 47. s 65.5 Percentl irelrease 1n score e ay 18 1 2 Rheometer at 144 C.: 6 6 1M 86 155 Maxunum torque 59. 0 64. 7 62. 9 64. 4 62. 2 59. 0 t2 8. 0 16. 2 17. 0 14. 5 13. 3 14. 6 tgo 22. 5 33. 3 31. 6 29.0 27. 3 30. 7

In an oil-extended styrene-butadiene rubber master batch, the scorch delay is increased 122% when N-(2- benzothrazolyl)cyclohexylsulfenamide is used.

MASTERBATCH Parts SBR 1712 137.5 Furnace black (ISAF 65 .0 Zine oxide 3.0 Stearic acid 1.0 Hydrocarbon softener 1.5

Total parts 208.0

Stock G H Masterbatch 208.0 208.0 Sulfur 1. 75 l. 75 Santocure NS 1.2 1. 2 N-(2-benzothiazolyDcyclohe ylsulfenam e 1.0 Santoflex 13 2. 2. 0 Mooney scorch at 121 0.:

l 17. 5 38. 8 Percent increase in scorch delay 122 Rheometer at 153 (3.:

Maximum torque 53. 5 51. 8 7. 9 13. 0 21. 2 27. 2

The compounds of this invention where R is aryl or alkyl have bactericidal properties. Such compounds are toxic to a spectrum of microorganisms, including S. awreus, S. lyphosa, PS. aerzrginosa, and A. niger.

Although the invention has been illustrated by typical examples, it is not limited thereto. Changes and modifications of the examples of the invention herein chosen for purposes of disclosure can be made which do not constitute departure from the spirit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Vulcanizable diene rubber containing elemental sulfur vulcanizin'g, agent, an organic accelerating agent and an amount eifective to inhibit premature vulcanization of a compound of the formula wherein R is alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms in the ring, aralkyl of 7 to 8 carbon atoms, or aryl of 6 to 12 carbon atoms, R' is hydrogen, lower alkyl, cycloalkyl of 5 to 12 carbon atoms in the ring or RS- where R" has the same meaning as R and may be the same or difierent from R, T is benzothiazolyl.

2. Vulcanizable diene rubber containing elemental sulfur vulcanizing agent, an organic accelerating agent and 8 an amount efi'ective to inhibit prevulcanization of a compound of the formula T-ITISR wherein Ris alkyl of 1 to 18 carbon atoms, cyc-loalkyl of 5 to 12 carbon atoms in the ring, or aryl of 6 to 12 carbon atoms, R is hydrogen, and T is benzothiazolyl.

3. A composition according to claim 2 wherein R is n-hexyl.

4. A composition according to claim 2 wherein R is isobutyl.

5. A composition according to claim 2 wherein R is cyclohexyl.

6. Vulcanizable diene rubber containing elemental sulfur vulcanizing agent, an organic accelerating agent and an amount effective to inhibit prevulcanization of a compound of the formula wherein R is phenyl, R is phenylthio, and T is benzothiazolyl.

7. Vulcanizable diene rubber containing elemental sulfur vulcanizing agent, an organic accelerating agent and an amount effective to inhibit prevulcanization of a compound of the formula TNSR wherein R is aryl of 6 to 12 carbon atoms or cycloalkyl of 5 to 12 carbon atoms in the ring, R is H or RS where R" is aryl of 6 to 12 carbon atoms or cycloalkyl of 5 to 12 carbon atoms in the ring and T is homethiazolyl.

8. The composition, according to claim 1, Where R is lower alkyl or cycloalkyl of 5 to 12 carbon atoms in the ring.

References (Zited UNITED STATES PATENTS 3,513,139 5/1970 Coran 260-79.5

JOSEPH L. SCHOFER, Primary Examiner C. A. HENDERSON, 1a., Assistant Examiner US. Cl. X.R.

260-302 R, 305 R, 307 D, 309.2 R, 784, 785, 786, 809, 999 

